1. Technical Field
The present invention pertains to an improved method and apparatus for interconnecting traction cleats and cleat receptacles for athletic shoes. Although the preferred embodiments disclosed herein are used primarily in golf shoes, it is to be understood that the interconnection method and structure have application in any shoe that utilizes traction cleats that are selectively attachable to a shoe.
2. Terminology
It is to be understood that, unless otherwise stated or contextually evident, as used herein:                The terms “upper”, “top”, “lower”, “bottom”, “vertical”, “horizontal”, etc., are used for convenience to refer to the orientation of a cleat and receptacle when attached to a shoe sole resting on the ground and are not intended to otherwise limit the structures described and claimed.        The terms “axial”, “axially”, “longitudinal”, “longitudinally”, etc., refer to dimensions extending parallel to the axis about which the cleat is rotated in the receptacle and substantially perpendicular to the shoe sole.        The terms “radial”, “radially”, “lateral”, ‘laterally”, etc., refer to dimensions extending perpendicularly from the cleat rotational axis and substantially parallel to the shoe sole.        The terms “angle”, “angular”, “rotationally”, etc., unless otherwise stated refer to rotation dimension about the cleat rotational axis.        The terms “attach”, “attachment”, etc., pertain to a longitudinal engagement between the cleat and receptacle that prevents inadvertent axial displacement of the cleat relative to the receptacle.        The terms “lock”, “locking”, etc., pertain to preventing inadvertent rotational movement between the attached cleat and receptacle.        
3. Discussion of the Prior Art
Replaceable traction cleats are designed to attach and lock into receptacles embedded in the outsole of a shoe. Typically, attachment is effected by means of a threaded stem extending from the top surface a cleat hub and engaging a correspondingly threaded socket in a shoe-mounted receptacle. The engaged thread surfaces provide the attachment by preventing longitudinal movement between the stem and socket. Examples of such an arrangement may be found in U.S. Pat. No. 5,036,606 (Erich), U.S. Pat. No. 6,272,774 (Kelly), U.S. Pat. No. 6,305,104 (McMullin), U.S. Pat. No. 6,823,613 (Kelly et al), U.S. Pat. No. 6,834,446 (McMullin), U.S. Pat. No. 7,107,708 (Kelly et al) and U.S. Pat. No. 7,137,213 (Kelly et al). Examples of other cleats that are useable in such arrangements may be found in U.S. Pat. No. 6,305,104 (McMullin), U.S. Pat. No. 6,675,505 (Terashima), U.S. Pat. No. 7,040,043 (McMullin). The entire disclosures in all of those patents are expressly incorporated herein by this reference. The receptacles used in the interconnection arrangements disclosed in the aforesaid patents necessarily have a relatively large longitudinal (i.e., vertical) profile in order to accommodate the longitudinal space needed for: (a) the threaded engagement between the receptacle and cleat stem; and (b) the locking components provided on the receptacle and cleat that gradually engage as the stem is rotated further into the socket and prevent inadvertent loosening of the interconnection between these two components. Typically, the receptacles in these arrangements have a longitudinal dimension on the order of 6 mm or greater. This dimension of the receptacle dictates a minimum thickness of the outsole of the shoe in which the receptacle is embedded. It is desirable that the receptacle be shorter in length in order to permit a thinner and less costly outsole, and because many golfers desire a thinner outsole to improve their feel for the terrain.
In order to prevent inadvertent rotation of the cleat stem relative to the socket, it is known to provide a locking arrangement such as that disclosed in the Kelly '774, Kelly, '613, Kelly et al '708 (Kelly et al) and Kelly et al '213 patents. These locking arrangements typically include teeth projecting radially from the socket exterior on the receptacle which increasingly engage, as a function of axial insertion of the stem, locking posts, or the like, projecting longitudinally from the cleat hub in spaced relation to the threaded stem.
The attachment arrangement shown in U.S. Pat. No. 5,768,809 (Savoie), instead of attaching the cleat and receptacle by using a threaded stem to engage a correspondingly threaded socket for engagement, has a post with three radially extending retaining members at its distal end. The retaining members are received axially through retainer-matching contoured openings in a receptacle cavity end wall and rotated in the cavity to an angular position past the contoured openings in which the cavity end wall prevents longitudinal movement of the retaining members. Locking structures within the cavity and at the radial extremities of the retaining members are engaged to minimize inadvertent rotational movement of the retaining members. In order to maximize retention in the cavity, the retainer members are relatively thick in their longitudinal dimension to minimize retaining member distortion under stress. Commercial embodiments of this arrangement are sold under the Q-LOK trademark and have retaining members with a vertical thickness of approximately 3 mm at their thickest part. The receptacle cavity must be sufficiently deep to receive the retainer members, which typically requires that the overall receptacle longitudinal dimension be at least 6 mm. As noted above, this dimension of the receptacle dictates a minimum thickness of the outsole of the shoe in which the receptacle is embedded and it is desirable that the receptacle be made thinner in length in order to permit the outsole to be thinner, thereby making it less costly to manufacture and providing the golfer with a better feel for the terrain.
It has been found that reliability of the locking arrangement for the attachment structure disclosed in the aforesaid Savoie patent leaves something to be desired. Specifically, the post and retaining members are a relatively rigid unitary structure, and the outer peripheries of the retaining members are flush against the cavity periphery. As a consequence, lateral forces during use are applied directly through the cavity wall to the unitary post and retaining members, tending to jar and loosen that unitary structure, displacing it from its locking structure in the cavity and permitting it to rotate in the cavity.
In other prior art locking arrangements the rotationally locked position of the cleat relative to the receptacle may be imprecise, depending on manufacturing tolerances or inherent features of the design. It is desirable to assure that locking structures on the cleat and receptacle provide for precision and reliable locking in desired rotational orientations of cleat relative to the receptacle.
Early golf cleats attached to a receptacle in the sole of the shoe using standard screw threads on a stem and in a socket requiring as many as ten 360° revolutions to secure the cleat in the receptacle against the outsole. Attempts at locking involved compressing the top of the cleat hub against the outer surface of the outsole to effect a friction fit. However, in practical use, this friction fit did not prevent the cleat from backing itself out from over time. In addition, there was no specific stopping point which alerted the installer of the cleat that the stem had been screwed in far enough; that is, there was no “stop” and no visible, audible or tactile indication that full insertion had been achieved.